Method for producing artificial fibers



Nov. 19, 1968 JOICHI KITAJIMA E 3,412,191

METHOD FOR PRODUCING ARTIFICIAL FIBERS Filed Oct. 22. 1965 I FIG 2 22 7 5 United States Patent 3 412,191 METHOD FOR PRODiJCING ARTIFICIAL FIBERS Joichi Kitajima, Kyohei Nose, and Shigeru Kikuchi, Ohtake-shi, Japan, assignors to Mitsubishi Rayon Co., Ltd., Tokyo, Japan, a corporation of Japan Filed Oct. 22, 1965, Ser. No. 501,684

Claims priority, application Japan, Dec. 18, 1964,

11 Claims. (Cl. 264181) ABSTRACT OF THE DISCLOSURE A portion of at least one spinning solution is extruded directly into a coagulating bath from spinning orifices disposed within said bath to form filaments, while the other portion of said spinning solution is first extruded into a gaseous medium and then directed into the coagulating bath to form filaments.

This invention relates to a method for producing novel artificial fibers.

In extruding two or more spinning solutions into one coagulating bath and taking up the resulting filaments from the bath according to conventional spinning methods, it is almost impossible to adopt coagulating conditions most suitable for every spinning solution, in view of variance in properties and spinnability. Particularly the takeup speed of filaments from the coagulating bath is restricted by that of filaments obtained from the spinning solution having the lowest jet stretchability (maximum take-up-roll speed attainable) resulting in lowering of productivity.

There has also been proposed a method in which two or more spinning solutions are extruded at the same time into one coagulating bath each from a different jet. (United States Ser. No. 383,789, British patent application No. 31,5 14/ 64, German patent application M 62,144. According to the above method, however, respective spinning solutions show different coagulation behavior and jet stretchability (especially in terms of maximum takeup roll speed attainable) in a common coagulating bath and hence it is difiicult to produce fiber bundles at a high spinning velocity and with good spinnability.

An object of the present invention is to provide a method for producing artificial fibers excellent in fiber properties at a high rate of productivity and with good spinnability when two or more spinning solutions are simultaneously extruded into one coagulating bath.

Another object of the invention is to produce artificial fibers having different fiber properties using one spinning solution and one coagulating bath.

Further objects of the invention will be clear from the description that follows:

These objects of the present invention are achieved by simultaneously extruding at least one spinning solution simultaneously from orifices disposed inside and outside of a coagulating bath, passing the extruded streams of the solution(s) from the orifices disposed outside of the coagulating bath through a gaseous medium and then the coagulating bath, passing the extruded streams of the solution(s) from the orifices disposed inside of the coagulating bath through the coagulating bath, taking the thus coagulated filaments out of the coagulating bath and subjecting these filaments to after-treatments.

In the present invention, a part of the spinning solution is extruded directly into the coagulating bath from spinning orifices disposed inside of the coagulating bath to form filaments, while the other part of the spinning solutions is first extruded into a gaseous medium and is then directed into the coagulating bath to form filaments,

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which are taken out of the coagulating bath together with the filaments directly extruded into the coagulating bath. The spinning solution to be directly extruded into the coagulating bath and the spinning solution to be first extruded into a gaseous medium may be the same or different. In case a spinning solution having high coagulating velocity and low jet stretchability is first extruded into a gaseous medium (ordinarily air or other inert gaseous atmosphere, the same shall apply hereinafter) from orifices disposed outside of the coagulating bath and is then directed into the coagulating bath, it is possible to greatly improve the jet stretchability of said spinning solution, in general, with the result that the spinning velocity of artificial fibers as a whole can be markedly improved and fiber bundles having execellent fiber property can be obtained.

Even in the case where at least two spinning solutions are to be simultaneously extruded from each orifice of a partor all of the orifices, spinnability can be greatly improved by extruding the spinning solutions first into a gaseous medium from orifices disposed outside of a coagulating bath and then directing them into the coagulating bath.

Generally, when two or more spinning solutions are extruded from one orifice while forming distinct phases without being completely dispersed, there are some cases where spinnability deteriorates due to the dilference in physical characteristics between the two solutions or the extruded filaments are split during the fiber production step or textile processing step due to insufi'lcient adhesion between the phases. Such drawbacks, however, can be overcome by extruding said spinning solutions from orifices disposed outside of a coagulating bath. Even when one spinning solution is employed in the present invention, it is possible to obtain artificial fibers having various specific effects, since the filaments extruded directly into a coagulating bath and those first extruded into a gaseous medium differ in physical and aesthetic fiber properties. For example, when filaments difier in shrinkages, a bulky ya-rn excellent in hand and appearance is obtained by shrinking the filaments in a relaxed state, and when the filaments differ in cross-sectional shape or luster, an artificial fiber having a specific aesthetic effect is obtained. An artificial fiber comprising filaments different in crosssectional shape can be easily obtained by varying the shape in cross-section of orifices disposed outside of the coagulating bath.

Preferable spinning solutions are those containing cellulose derivatives, polyvinyl alcohols, polyacrylonitrile, acrylonitrile copolymers, polyvinyl chloride, polyvinylidene chloride or polyurethane. As specific examples, however, spinning solutions of polyesters, polyamides or polyolefins are used as well. The spinning solution to be used in the present invention is ordinarily in the form of a solution or emulsion, but one in a molten state is also usable. Further, it is not objectionable that the spinning solution contains a monomer or so-called prepolymer, thereby bringing about such a reaction as polymerization or the like in the coagulating bath.

When two spinning solutions are to be used, those different in polymer composition or in polymerization degree may be employed. Further, spinning solutions identical in polymer composition and polymerization degree but different only in polymer concentration, solution temperature, kind of solvent or additive are also usable. In one of the most preferred embodiments, a spinning solution of polyurethane is extruded from orifices disposed inside of the coagulating bath and a spinning solution of acrylonitrile copolymer is extruded through orifices dis posed outside of the coagulating bath so that the ratio of polyurethane to acrylonitrile copolymer becomes 1-60:99:40.

In practice, the spinning procedures may be carried out using a plurality of spinning jets in combination, and some of the jets are disposed in the coagulating bath while the others are disposed out of the coagulating bath. It is, however, desirable to use one spinning jet and to dispose a part of the orifices in the coagulating bath and the other part out of the bath.

The spinning method of the present invention Will be illustrated below with reference to the accompanying drawing, in which:

FIG. 1 illustrates the present spinning method when two spinning jets are used.

FIGS. 2 and 3 illustrate the spinning method when one jet is used.

FIGS. 4 and 5 are a longitudinal cross-section and a bottom view respectively of a jet having orifices to be placed inside and outside of a coagulating bath.

In the drawing, 1 is a jet having orifices positioned out of a coagulating bath, 2 is a jet having orifices positioned in a coagulating bath, 3 is a jet having orifices disposed both in and out of a coagulating bath, 4 is the liquid surface of a coagulating bath, 5, 6 and 7 are conduits for spinning solutions, 8 and 9 are filaments, 10 is a bundle of collected filaments, 11 is a spinning bar guide, 12 is a coagulating liquid-introducing pipe, 13 is a coagulating liquid-overflow pipe, 14 is a coagulating liquid-supplying nozzle, 15 is a valve and 16 is a funnel-like tube.

In FIGS. 4 and 5, 17 is a cap nut, 18 is a conduit for a spinning solution to be directly extruded into a coagulating bath, 19 is a conduit for a spinning solution to be first extruded into a gaseous medium, 20 is the body of a jet assembly, 21 is a bolt, 22 is a cap nut, 23 is a perforated plate for uniformly distributing in each orifice a spinning solution to be extruded into a gaseous medium, 24 and 25 are spinneret plates, 26 and 27 are gaskets, 28 is a ring, 29 is a bolt, and 30 and 31 are orifices. The orifice 31 has a diameter of 0.08 mm. and a circular cross-section. Twenty orifices are concentrically perforated on the spinneret plate 25 at intervals of 5 mm. Further, seventy orifices are perforated at intervals of 3 mm. on the doughnut like spinneret plate 24.

In FIG. 1, a spinning solution fed from conduit 5 is first extruded into a gaseous medium from jet 1 and then directed into the coagulating bath to form filaments 8. On the other hand, a spinning solution fed from conduit 6 is extruded from jet 2 directly into the coagulating bath to form filaments 9. These filaments are collected, if necessary, by means of guide 11 and are taken out of the coagulating bath.

In FIGS. 2 and 3, a part of the spinning solution is first extruded into a gaseous medium from the orifices perforated in the indented portion of the jet 3 and then directed into the coagulating bath to form the filaments 8. On the other hand, the other part of the spinning solution is directly extruded into the coagulating bath from the orifices perforated in the extruded portion of jet 3 to form filaments 9. When a draft tube is used in the coagulating bath, it is possible to improve the spinning velocity. In place of using the draft tube, Tiele typespinning may be effected as shown FIG. 2.

There is no particular limitation with respect to the relative positions or orifices to be disposed inside and outside of a coagulating bath. For purposes of ease in spinning operations, however, it is desirable to use a jet of such structure that the orifices to be disposed outside of the coagulating bath are arranged on outer periphery of the orifices to be disposed inside of the coagulating bath. The use of one jet having both groups of orifices to be disposed inside and outside of a coagulating bath gives the advantage that the spinning apparatus can be made compact. In addition thereto, there are such advantages that, by varying the arrangement of respective orifices, the configuration of filaments 8 and 9 in the resulting fiber bundle can be freely changed, and that said two kinds of filaments can be distributed relatively uniformly.

The shape, size and arrangement of orifices are not specifically limited but when the diameters of orifices disposed outside of a coagulating bath are excessively small, extruded filaments tend toadhere to each other. Therefore diameters of more than 1.0 mm. are desired. The distance between the orifices and the liquid surface of coagulating bath through which the extruded stream of spinning solution passes is preferably from 1 to 100 mm. In order to prevent the filaments from mutal adhesion, the distance of travel should be made shorter as the diameter of orifices are madesrnaller, and a distance of 3 to 30 mm. is desired. The gaseous medium occupying the space between the liquid surface of coagulating bath and the orifices is ordinarily air, but the presence of heated vapour of the coagulating bath or other inert gas is not objectionable. As a special example, said space may be filled with a specific liquid other than the coagulating liquid.

The present invention is preferably adopted for spin ningv a spinning solution of an acrylonitrile polymer in combination with a spinning solution of a polyurethane.

The polyurethane to be used in the present invention are elastic polymers formed by reacting diamine or hydrazine with interpolymers having terminal isocyanate groups which are obtained by the reaction of polyols with organic diisocyanates. Preferable polyurethane are those which when formed into fibers have a reversible elongation of,100700% and an initial modulus of 0.01-0.5 g./d. The polyols to be used in the present invention are polymeric polyether glycols having a molecular weight of 600-4000, ahydroxyl value of 30-185 and an acid number of up to 2, or aliphatic polyesters having terminal hydroxyl groups. The most preferable polyols include polyoxy tetramethylene glycols having a molecular weight of 1000-2000, polyethylene adipate and polycaprolactone. As the organic diisocyanates, aromatic diisocyanate, particularly diphenylmethane 4,4 diisocyanate, are employed. There may also be used copolymers in which crystalline high melting segments derived from polyurea, polyamides, bisureylene polymers and polyesters and low melting amorphous polymers derived from polyesters, polyethers and hydrocarbon polymers are alternately arranged in the form of blocks.

As the acrylonitrile polymers, there are ordinarily used polyacrylonitrile and acrylonitrile copolymers containing more than by weight of acrylonitrile. Examples of acrylonitrile copolymers are acrylonitrile-vinyl acetate, acrylonitrile-methyl acrylate and acrylonitrile-vinyl acetate-sodium vinyl benzenesulfonate copolymers or interpolymers.

As solvents for the polyurethane and acrylonitrile polymers, dimethyl acetamide, dimethyl formamide and dimethyl sulfoxide are preferred. The coagulating bath to be used is peferably an aqueous bath which contains 20- 70% by weight of either of said organic solvents and which is maintained at a temperature of 10-65C. The bath temperature may be lower than 10 C. When the solvent content is more than 70% by weight, the polyurethane elastomer is insufiiciently coagulated, whereas when said content is less than 20% by weight, the acrylonitrile polymer is coagulated too quickly, whereaby the fiber properies are lowered.

The filaments taken out of the coagulating bath are washed, stretched and thermally treated. The washing is preferably effected in hot water at 30-90 C. The washed filaments are stretched ordinarily to 1.1-7 times in hot water at 70100 C. A more preferable stretch ratio is 2-7 times. It is also possible to effect the washing simultaneously with the stretching. The stretched filaments are then subjected to shrinking treatment in a relaxed state in hot water at 801 10 C., either after or without being cooled to about 5060 C. The shrinking treatment may be carried out in steam at -140 C. A shrinkage of 10-30% is preferable. According to the shrinking treat ment, the filaments after drying are improved in knot strength, elongation and dye-receptivity. The filaments subjected to shrinking treatment are dried at 100-150 C. in order to remove voids formed in the filaments at the time of coagulation. In the present invention, however, there is no particular limitation with respect to spinning, and after-treating conditions. For instance, the filaments taken out of the coagulating bath may be stretched 2 times while washing in hot water at 100 C., dried at 100- 150 C., stretched 3 times at 120150 C. and then heat shrunk at 140160 C.

The thus obtained artificial fiber bundle comprising polyurethane and acrylonitrile filaments may be subjected to false twisting to give a texturized yarn or it may be subjected to drawing and cut to give an elastic spun yarn.

In accordance with the present invention, it is also possible to conjugate spin a spinning solution of polyurethane elastomer and a spinning solution of acrylonitrile polymer from orifices disposed outside of a coagulating bath and to spin a spinning solution of polyurethane elastomer or acrylonitrile polymer from orifices disposed inside of the coagulating bath. When spinning solutions of polyurethane and acrylonitrile polymer which are markedly different in jet stretchability are conjugate spun from orifices disposed outside of a coagulating bath, spinnability is greatly improved and the two polymers show increased mutual adhesion to give a bulky yarn excellent in dimension stability.

The present invention is further applied to the spinning of two kinds of acrylonitrile polymer spinning solutions. There is no particular limitation in the preparation process, composition and viscosity of the acrylonitrile polymer spinning solutions. When two kinds of acrylonitrile polymer spinning solutions are to be used, it is desirable to extrude a high concentration spinning solution having a poorer jet stretchability from orifices disposed outside of the coagulating bath and a spinning solution having a better jet stretchability from orifices disposed inside of the coagualting bath.

The following examples illustrate the present invention.

EXAMPLE 1 A prepolymer obtained by reacting polycaprolactone having terminal hydroxyl groups (average molecular weight: 2060, hydroxyl value: 54.1, acid number: 0.2) with diphenylmethane-4,4'-diisocyanate at a polyol-diisocyanate molar ratio of 1:2 was dissolved in dimethylacetamide. To the solution, a dimethylacetamide solution of ethylene diamine was added so that the molar ratio of prepolymer to diamine became 1:1. The resulting solution having a polymer concentration of 23.2% was used as spinning solution A.

On the other hand, a copolymer comprising 93% of acrylonitrile and 7% of vinyl acetate and having a specific viscosity of 0.17 (measured at 25 C. in dimethylformamide at a concentration of 0.1 g. polymer/ 100 cc. dimethyl formamide) was dissolved in dimethylacetamide. The resulting solution having a polymer concentration of 23.5% was used as spinning solution B.

The spinning solutions A and B were subjected to spinning according to the embodiment shown in FIG. 3, using the jet indicated in FIGS. 4 and 5. Namely, the spinning solution B was extruded into air at 40 C. from orifices (72 orifices) disposed outside of a coagulating bath, was passed through air for distance of 5 mm. and was then directed into the coagulating bath comprising 50% of dimethylacetamide and 50% of water and maintained at 40 C. On the other hand, the spinning solution A was directly extruded into the coagulating bath from orifices (14 orifices) disposed inside of the coagulating bath. The resulting filaments were taken out of the coagulating bath, washed with hot water at 70 C., stretched to 5 times in hot water at 95 C., immediately cooled to 60 C., thereafter shrunk by 25% in boiling water, dried on a hot roller at 125 C. and then taken up on a bobbin. The final take-up velocity of the filaments was 150 m./min. The polyurethane elastic filament had a total denier of 63, a strength of 1.3 g./d. and an elongation of 210%, while the acrylonitrile filament had a monofilamentary denier of 3.1, a strength of 2.6 g./d., and an elongation of 34%.

The filaments were then drafted to cut at a draft ratio of 1.6 and a roller gauge of mm. by means of a two line system direct spinning machine provided with a trumpet and were taken up on a bobbin while applying twist of 500 times/m. In order to fix the twisting, the spun yarn was treated with steam at 105 C. for 30 minutes to obtain an elastic spun yarn having a yarn count of 20s, a strength of 0.83 g./d., an elongation of 122%, a stretchability of 65.8%, and a boiling water shrinkage of 2.7%.

For reference, both spinning solutions A and B were directly extruded into the coagulating bath under the same conditions as above. In this case, the spinning could not be effected at a final take-up velocity of more than 50 m./min., since the jet stretchability of the spinning solution B was low, and the acrylonitrile fiber was markedly delustered due to void formation.

EXAMPLE 2 The spinning solution B in Example 1 was extruded into air from orifices (40 orifices) disposed outside ofa coagulating bath, passed through air for a distance of 5 mm., and was then directed into the coagulating bath comprising 45% of dimethyl acetamide and 55% of water which was kept at 55 C. 0n the other hand, the spinning solution A in Example 1 was directly extruded into the coagulating bath through orifices (10 orifices) disposed inside of the coagulating bat-h. The resulting filaments were taken out of the coagulating bath, washed with hot water at 70 C., stretched to 5 times in boiling water, immediately cooled at 50 C., shrunk by 20% in boiling water, dried on a hot holler at 125 C., and were then taken up on a bobbin. The polyurethane elastic filament had a total denier of 65, a strength of 0.79 g./ d. and an elongation of 245%, while the acrylonitrile filament had a monofilamentary denier of 6.0, a strength of 3.2 g./d. and an elongation of 24.7%. The filaments were subjected to a preliminary tension of 0.1 g./d. and were false-twisted under the conditions of'a spindle speed of 50,000 r./min., a heater temperatureof C., a heater length of 300 mm., a stretch ratio between two rolls of 1.10, and a number of false-twisting of 1400 times/m. The resulting processed yarn was treated with steam at 110 C. for 30 minutes. The texturized yarn thus obtained had a strength of 1.9 g./d., an elongation of 110% and a recovery after 50% elongation of 96%.

EXAMPLE 3 A prepolymer obtained by retracting polyethylene adipate having terminal hydroxyl groups (hydroxyl value: 97, acid number: 1, average molecular weight: 1940) with diphenylmethane-4,4'-diisocyanate at a polyester to diisoycanate molar ratio of 2:3 was dissolved in dimethyl acetamide. To the solution, a dimethyl acetamide solution of ethylene diamine was added so that the molar ratio of prepolymer to diamine became 1:1. The resulting solution having a polymer concentration of 22% was used as spinning solution C.

On the other hand, a copolymer comprising 93% of acrylonitrile and 7% of vinyl acetate and having a specific viscosity of 1.8 was dissolved in dimethyl acetamide and the resulting solution having a polymer concentration of 22% was used as spinning solution D.

The spinning solutions C and D were subjected to spinning using the same spinneret as in Example 1. Namely,

the spinning solution D was extruded at 60 C. through from orifices disposed outside of a coagulating bath, passed through air for distance of 5 mm., and directed into the coagulating bath comprising 35% dimethyl acetamide and 65% water which was maintained at 50 C. On the other hand, the spinning solution C was directly extruded into the coagulating bath. The resulting filaments were taken out of the coagulating bath, washed while being stretchedto 1.5 times in boiling water, stretched to 4 times in water at 80 C., cooled to 60 C., shrunk by in boiling water, dried on a hot roller at 120 C., and were then taken up on a bobbin. The final take-up velocity was 180 m./min. When the takenup filaments were brought into a non-tension state, only the polyurethane filament shrunk and the acrylonitrile filament was brought into a finely looped state and was exposed on the surface of the resulting fiber bundle. The fiber bundle was excellent in hand and suitable in elasticity.

EXAMPLE 4 Example 3 was repeated except that a funnel-like tube as shown in FIG. 2 was used in the coagulating bath. The flow rate of the coagulating liquid at the lower part of the tube was m./-min. In this example, the spinning velocity could be further increased, and the spinning was effected stably with a final take-up velocity of 250 m./min.

EXAMPLE 5 The spinning solution D in Example 3 was spun at C., using the same spinneret as in Example 1 (provided that each of the orifices outside of the coagulating bath had a cross-section in the form of a Y. The coagulating bath was composed of 50% of dimethyl acetamide and 50% of water, and was kept at 40 C. The resulting filaments were taken out of the coagulating bath, stretched to 5 times while being washed in boiling water and 'were dried on a hot roller at 140 C., and taken-up to skein. The final take-up velocity was 45 m./min. The skein was subsequently shrunk with saturated steam at 135 C. in a steam oven. The filaments extruded through the orifices disposed outside of the coagulating bath had a Y shaped cross-section and were markedly lustrous. Further, the filaments extruded through the orifices disposed inside of the coagulating bath were exposed out of the resulting fiber bundle in the form of waves and were commingled with the filaments having a Y shaped cross-section. Thus, the fiber bundle was excellent in hand and aesthetic efiect.

What we claim is:

1. A method for producing artificial fibers which comprises extruding at least one spinning solution simultaneously from orifices disposed inside and outside of a coagulating bath, passing the extruded stream of solution from the orifices disposed outside of the coaguating bath through a gaseous medium and then the coagulating bath, passing the extruded streams of solution from the orifices disposed inside of the coagulating bath through the coagulating bath, taking thus coagulated filaments out of the coagulating bath and subjecting these filaments to after-treatments.

2. A method according to claim 1, wherein at least one spinning solution having a better jet stretchability is extruded from orifices disposed inside of the coagulating bath and at least one other spinning solution having a poorer jet stretchability is extruded from orifices disposed outside of the coagulating bath.

3. A method according to claim 1, wherein two acrylonitrile polymer solutions are extruded.

4. A method according to claim 1, wherein a spinning solution of polyurethane is extruded from orifices disposed inside of the coagulating bath and a spinning solution of acrylonitrile polymer is extruded from orifices disposed outside of the coagulating bath.

5. A method according to claim 4, wherein the ratio of the amount of polyurethane extruded to the amount of acrylonitrile polymer extruded is 1-60199-40.

6. A method according to claim 4, wherein the coagulating bath contains 20-70% of a solvent selected from the group consisting of dimethyl formamide, dimethyl acetamide and dimethyl sulfoxide and is maintained at a temperature of from 10 to C.

7. A method according to claim 6, wherein the filaents taken out of the coagulating bath are washed, are stretched to 1.1-7 times in hot water at -100" C. and are then subjected to shrinking treatment.

8. A method according to claim 1, wherein the spinning solution extruded from the orifices disposed outside of the coagulating bath is passed through the gaseous medium for distance of from 1 to mm.

9. A method according to claim 1, wherein the diameters of the orifices disposed outside of the coagulating bath are more than 1.0 mm.

10. A method according to claim 1, wherein a jet having orifices to be disposed both inside and outside of the coagulating bath is used.

11. A method according to claim 1, wherein at least two spinning solutions are extruded from at least a part of the orifices.

References Cited UNITED STATES PATENTS 3,088,188 5/1963 Knudsen 264-482 X 3,088,793 5/1963 Knudsen et a]. 264-482 3,131,429 5/1914 Okamura 18-8 JULIUS FROME, Primary Examiner.

J. H. WOO, Assistant Examiner. 

